We have just received our first shipment of the long overdue CSA Polymer mag well adapters. Price $85.00. Our first impressions are mixed, I thought they were better than I expected. They include a modified bolt release catch that should hold the bolt open after the last rd is fired. I have concerns that if a mag is rammed in hard when the bolt is locked back the polymer retaining lips may be broken, only time will tell. I have concerns that the bolt hold open catch will have enough spring power to eject an empty mag, again time will tell. These adapters appear flimsy but these are my first impressions only. On all the early guns the front of the mag well on the rifle will need to be machined to allow full insertion of the magazine.

I do not see any reason why these mag well adapters will not work in an CZ 858 but extra machining will be required at the rear of the rifle mag well in addition to what has to be removed from the front. On the rifle I looked at the bolt release catch would also require some additional fitting.

We have had to wait so long for these CSA adapters that we have already taken the initiative and commissioned Brugger & Thomet to manufacture their own Mag Well adapter, the B&T adapter is unique to them and they are machined from Aluminum. Hopefully we will see them before Christmas. These have been designed to be used in the 7.62x39 CZ 858 using the 10 rd XCR Pistol magazine. There is no bolt catch when using these, but then the AK47 never had a bolt catch. We see no reason why this should not work in the CSA rifles in .223 using the AR15 mags. We have plenty of 10 rd mags in stock, in both calibers, price $29.95. We do know that the adapter will require a small amount of metal to be machined out of the front of the magazine well in the rifle, we are hoping that this a DIY job, but no details at this time. After this material is removed it will not stop you from using the original mags when the mag well adapter is removed and the original mag catch and bolt release is reinstalled. We anticipate the retail to be $175.00.

Brugger & Thomet - CZ 858 Magwell adapter.

We will post more information as it becomes available.

I contacted CSA and it seems that the modification may be a bit more difficult and not a home jo

These are my first impressions on the CSA Magwell adapter from one short test so please do not read too much into them.
I have just examined three receivers with a view to fitting the CSA Magwell adapter, see following photo. Only the CSA Carbine in .223 is ready to accept the adapter as this receiver has material milled out at the front of the mag well. Observe the difference at the rear of the mag well between the CSA and the CZ 858 receivers, it would appear that if we want to fit the CSA Magwell adapter to the CZ rifle we will need to machine the rear as well.

Top receiver is CZ 858 rifle 7.62x39. Middle is CSA Carbine in 7.62x39 and bottom is CSA Carbine in .223

Fitting: The new bolt stop dropped into the 7.62 CSA carbine but I had to file and polish it and hand fit to the CSA 223 carbine. I also replaced the supplied bolt stop spring with a stronger CZ 858 spring. Eventually I got her to work so that she would reliably catch the bolt when the charging handle was retracted with an empty mag inserted, the trick was to get her to release when the mag was removed and the bolt retracted slightly. I test fired with one mag of 10rds. ASC XCR-L .223 pistol mag. All fed reliably but the bolt catch engaged prematurely three times, trimming the nib on the catch back may solve this problem but then it may not engage on the mag follower. I found the magazine was a snug fit in the CSA Magwell adapter and would not drop free under any conditions.

Bolt catch engaged prematurely by live rd in magazine.

We have a machinist looking at these receivers and hopefully will report back in a week’s time the cost of machining both a CZ 858 and CSA 7.62x39 Carbine to accept the CSA Magwell adapter. We are also looking at further maching to make the bolt stop work reliably but I am not sure at this time if this will be required on all guns or not. Hand fitting that bolt stop was a PITA and not something we want to do on a regular basis.

I know that our Brugger & Thomett aluminum Magwell adapter has no bolt stop mechanism and we have required that the mags (Full or empty) will drop free. The B&T Magwell adapter will also require machining in the CZ 858 and CSA 7.62x39 receivers, it remains to be seen if it will drop straight in the CSA .223 caliber guns. The Brugger & Thomett adapter was designed to function in the CZ 858 7.62x39 rifle.

Remember this is a quick first test, we did not try the parts in more than three guns.

John, please read the link I posted above, I just received great news from CSA and I know that you still have some of the first models in stock and probably the complete data base of customers who bought the first model serial number

B&T Two thumbs up!

Wonderful work John.

Like Bfiles, I too am curious how the magazine release functions fired from the left side and right side. I figure it may be a bit of a pain for southpaws but if it's easy to push with the index finger it might work quite well.

Ideally this new 7.62x39 magazine adapter would be great with the CSA Compact. I would suggest that you provide a few of these units installed on the CSA Compact Carbines. Like many vz58 fans, I would be tempted to own both versions. While I don't mind cleaning my rifles, I don't want to be tinkering around with them all the time either.

Well, i am not sure, i got mine in september in 223 cal. I am looking forward to hearing the news. I been waiting for this for a while. I hope the b&t will work in 223. If u can figure out how to make the catch work properly ill order a polymer adapter for the time being and put it threw its passes. Aluminum would be much better.

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